A Creep Damage Model for Rock Mass Based on Internal Variable Theory

Abstract

The creep damage is discussed within Rice thermodynamic theory with internal state variable (ISV). A viscoelastic-viscoplastic model with damage is derived by giving the complementary energy density function and kinetic equations of ISVs. The viscoelastic equation covers classical component model, and three creep phases with hardening and damage effect can be described by this model. The model parameter cabibration is conducted through uniaxial creep test of analogue material by loading and unloading method. Then intrinsic thermodynamic properties in three creep stages are indicated. The thermodynamic state of material system tends to equilibrate without damage and depart from equilibrate with damage.